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digitalmars.D.bugs - [Issue 2873] New: typeof() for member functions evaluated incorrectly

reply d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=2873

           Summary: typeof() for member functions evaluated incorrectly
           Product: D
           Version: 2.029
          Platform: PC
        OS/Version: Windows
            Status: NEW
          Severity: major
          Priority: P2
         Component: DMD
        AssignedTo: bugzilla digitalmars.com
        ReportedBy: dsimcha yahoo.com


// Copied/pasted from std.range, added pragma.
template hasLength(R)
{
    pragma(msg, typeof(R.init.length).stringof);  // (uint())()
    enum bool hasLength = is(typeof(R.init.length) : ulong);
}

struct Foo {
    uint length() {
        return 0;
    }
}

const Foo foo;

static assert(hasLength!(Foo));  // Fails.

This is pretty serious because it makes important functionality in the new
Phobos unusable.  However, an easy workaround to fix Phobos until the
underlying DMD bug gets fixed is:

enum bool hasLength = is(typeof(R.init.length) : ulong) ||
                      is(typeof(R.init.length()) : ulong);

Also, what the heck is a (uint())() ?


--
Apr 21 2009
next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=2873


Masahiro Nakagawa <repeatedly gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |k-foley onu.edu



10:04:17 PDT ---
*** Issue 3508 has been marked as a duplicate of this issue. ***

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May 02 2010
prev sibling next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=2873


Masahiro Nakagawa <repeatedly gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
                 CC|                            |repeatedly gmail.com
         Resolution|                            |INVALID



17:52:04 PDT ---
Since adding  property, this behavior isn't a bug. length method should be a
property. Please use  property for length method.

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May 04 2010
prev sibling next sibling parent d-bugmail puremagic.com writes:
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bearophile_hugs eml.cc changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |bearophile_hugs eml.cc



Masahiro Nakagawa, I am not sure I understand this bug report and your answer
well. But if I understand them, then then if you are right, and length method
should be a property, then the compiler has to give a compile time error if you
try to define a non-property length method, otherwise it's too much easy to
write a bug.

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May 04 2010
prev sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=2873




20:33:06 PDT ---


 Masahiro Nakagawa, I am not sure I understand this bug report and your answer
 well. 


Old D's property is a syntactic sugar(member function automatically becomes
property), so typeof() should have evaluated .length and .length() correctly.
But now, D has  property. User can choose property or non-property.


 But if I understand them, then then if you are right, and length method
 should be a property, then the compiler has to give a compile time error if you
 try to define a non-property length method, otherwise it's too much easy to
 write a bug.


I agree because I can't image non-property length. I think D's compiler should
print warning message if user tries to define non-property length.

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May 04 2010